The Anthropology of Catastrophe: Volcanoes

Humans have always been afflicted by natural catastrophes ranging from tectonic to weather related and, possibly, even impacts from space! But none, perhaps, have found the significance both culturally and destructively, as the volcano. Throughout the history and prehistory of man, volcanoes have erupted, obliterating entire islands, destroying settlements and cities, ruining local crops and affecting climate on a global scale. And, while volcanoes have also long been anthropomorphized to attribute blame or malevolent intent, not a single one ever intended to cause human destruction.Notable volcanic eruptions in the archaeological and historical record include Thera, Vesuvius, Mt. St. Helens, and Mt. Pinotubo, among many others.

VesuviusErupted 79 CE â€“ Pompeii and Herculaneum, ItalyThis was the first documented volcanic eruption in history and was responsible for the instantaneous deaths of thousands who found themselves in the path of the eruptionâ€™s heat, poison gases, pyroclastic flows of rock and ash, and the sheer trauma of the blast wave. As most people who have heard of Pompeii are no doubt aware, the site is often billed as an archaeologistsâ€™ dream since it represents a â€œsnapshotâ€ in time. The main reason is that settlements like Pompeii and the closer Herculaneum were inundated with volcanic ash and rock in a rapid and hot pyroclastic flow, trapping some residents in death poses until excavated nearly 2000 years later. Recent discoveries at Herculaneum include a wooden throne, preserved in the volcanic ash for over 1900 years.

Thera (Santorini) Erupted 1627-1600 BCE Aegean SeaGenerally accepted to have brought about the demise of the Minoan civilization and ash layers from the eruption are evident in localities like Crete, and the Santorini archipelagos which includes Thera. The Minoan civilization spread across each of these and other Cycladic islands, with Crete being about 100 miles from Thera. In the Satorini archipelago is Akrotiri, a Minoan settlement buried by the 17th century BCE eruption in volcanic ash. Desturction from this eruption was primarily caused by pyroclastic flow, tsunami and ash deposits. For Minoan settlements on Thera and the Santorini island chain, civilization ended abruptly as they were vaporized, cooked, and buried alive. For the Minoan cities and settlements further away in Crete, they may have had a few more moments until the tsunami created by the massive amount of ash, rock, and other ejecta suddenly plunging into the sea, displacing the water. And, while some Minoan settlements did survive, the eruption of Thera is considered to have contributed greatly to the civilization’s demise.

Mt St Helens and Mt PinotuboErupted in 1980 in Washington, USA and 1991 on the Philippine Island Luzan, respectivelyMt. St. Helens was considered a major volcanic eruption, responsible for 57 deaths and thousands made homeless, not to mention the devastation to the environment. However, it small in comparison to its 20th century colleague Mt. Pinotubo, which erupted in the Philippines just a decade later. This one took 800 lives and left 100,000 or more homeless. The Pinotubo eruption was also 10 times larger than that of Mt. St. Helens. In the case of both of these eruptions, scientists and researchers were carefully monitoring the geologic activity associated with the volcanoes and were able to use the data to evacuate and warn local residents. Indeed, of the 800 killed by Pinatubo, the majority lost their lives due to the ash fall which mixed with rain and caused roofs to collapse.

In the case of each eruption, the cultural effects included the cost of rebuilding and recovering infrastructure and private property. The St. Helens eruption cost $1.1 billion to recover from the catastrophe. The residents of Luzon only faced about half that cost, but they, perhaps, suffered far more economically since the Luzon economy was ruined. Clark Air Base, which the U.S. occupied was evacuated and the Air Force never returned, which, by itself, would have spelled trouble for the local economy. The last I heard, the region is still trying to recover the economy and rebuild infrastructure.

How volcanoes destroyLava FlowsAlthough instantly associated with volcanoes, lava flows only account for a fraction of a percent of the total number of deaths due to volcanoes in the last xx years. Lava is slow and can be outrun, but it does damage property and infrastructure in places such as Hawaii where the Kilauea volcano regularly spews forth a basaltic magma that becomes lava as it leaves the ground.

GasesThese kill slightly more people than lava. Denser than air carbon dioxide and hydrogen sulfide are the most dangerous as they flow into and fill low lying areas. Carbon dioxide is colorless and odorless and can asphyxiate people who breath it unawares. Hydrogen sulfide has a “rotten egg” smell, but a single breath can kill in high enough concentrations. Fortunately, such concentrations are relatively rare. Other gases can also be problematic for humans, albeit indirectly. In 1783, the laki fissure eruption killed an estimated 10,000 Icelanders, but due to starvation and famine after the loss of crops and livestock due to long-term exposure to hydrogen fluoride.

Tephra, Ash, and pryoclastic flowsTephra includes the fragmented rocks and blocks ejected in the air by the eruption itself. Fortunately, tephra and ash typically affect the regions closest to the volcano, having increasing less effect the further from the eruption you go. Ash, however, can be ejected high into the atmosphere, allowing it to be deposited many miles away. But its that ash and rock that lands near the volcano that is the most problematic. Much of the tephra and ash comes back down into the volcano’s crater, but this often results in pyroclastic flow which can leave a wake of destruction in its path as hot ash and rock are forced down and out away from the volcano’s cone due to the force of the eruption.

Relatively few people have actually lost their lives due to tephra and ash falls, however, the danger ash poses most is the accumulation on the roofs of homes and buildings, particularly if the ash becomes wet. Wet ash soaks up water, and creates a very heavy mud, about 10 inches of which are sufficient to collapse a roof, injuring or killing the building’s occupants.

Pyroclastic flows have claimed far more victims, however, making this one of the more dangerous features of a volcanic eruption. 27 percent of the lives lost in recorded volcanic eruptions were due to pyroclastic flows, the effects of which are most notable in Pompeii and Herculaneum, where pryroclastic flows of ash, rock, gases, and bits of lava quickly rushed in along the ground, burying both cities. Residents had seconds to realize
what had occurred, and probably each killed instantly as the heat from the flows cooked their bodies and boiled their brains -the ash burying them along with the buildings, homes, and artifacts of their cities. Alun Salt discusses a recent find of a throne at Herculaneum at Clio Audio, describing the effects of pyroclastic flows and preservation of material remains.

Lahars and TsunamisAnother immediate killer from volcanic eruptions are the occasional lahars as well as the tsunamis some volcanoes create due to earth quakes caused by the eruption or pyroclastic flows that dump into the sea, displacing water. Lahar is an Indonesian word that refers to the mud flows created by large amounts of ash and water. The heat from a volcanic event can melt snow and ice and, as the resulting water mixes with ash, a mud is formed which then flows down the mountain, obliterating towns and settlements. Lahars and tsunamis are together responsible for a whopping 34% of the deaths that have been recorded due to volcanoes.

But that isn’t the most significant killer that results from a volcano. The most significant killer is, by itself, responsible for a full 30% of the deaths related to volcanoes (remember, lahars and tsunamis are two different things -17% each). That killer is post-eruption famine and disease that takes place months later. Gases and ash ejected into the atmosphere can affect crops and livestock and even global temperatures! 1816 was called the “year without summer” due to the eruption of Tambora in Indonesia the year before. Global temperatures dropped to between .4 and 1.0 Celsius and crops were affected around the globe. In Europe, particularly in Great Britain, a typhus epidemic that broke out that year was blamed on the unseasonably cold weather.

Volcanoes and Human Belief, Religion, and SuperstitionVolcanoes don’t seek human attention or appeasement. But its easy to see how others might think so. Humans have long had very tenuous relationships with their volcanoes, which remain oblivious to the anthropomorphizing applied by cultures in South America, Indonesia, Polynesia, and Mesoamerica. Volcanoes gods exist in many cultures even today and many sacrifices have been made to these gods in the way of virgins and material possessions in attempt to appease the god.

Perhaps the most familiar volcano god to Americans is Pele, since this legend is still told (albeit mostly tongue-in-cheek) in the state of Hawaii where the Kilauea volcano is still active. According to the legend, Pele is the goddess that lives in the volcano and she created (and is still creating) the islands of Hawaii.

In Japan, Mt. Fuji is the source of several myths and legends, including that the goddess Sengen resides there, tossing off the mountain any pilgrim of impure heart. Legend has it that the mountain was created in a single day at around 86 BCE, though the mountain itself can be geologically dated to as far back as 8500 BCE when it was volcanically created. There was, however, an eruption at around 86 BCE, which may have inspired the legend of its creation.

The myth of Atlantis, a story first created in two dialogs by Plato, may have had its inspiration in the oral stories that surrounded the fall of the Minoan civilization and the sudden demise of several of their cities. If true, Plato certainly embellished the account and modified it to fit the the lesson he was trying to teach through Critias and Timaeus, the two dialogs in which he mentions Atlantis. It is fascinating to consider the appeal that the story has on even modern humans and their beliefs.

Finally, it mustn’t be overlooked that the very term “volcano” and the study of volcanoes, “volcanology,” is derived from Vulcan, the Roman god of fire.

One might ask why bother living near such an unpredictable god? One reason, of course, is that the god provides a bounty by way of rich soils for cultivation and other resources such as an abundance of chert and obsidian needed for manufacture of stone tools.

For all the difficulties volcanoes have created for man, we, perhaps, have reaped far more benefit.

Professional archaeologist that currently works for the United States Forest Service at the Land Between the Lakes Recreation Area in Kentucky and Tennessee. I'm also a 12-year veteran of the U.S. Army and spent another 10 years doing adventure programming with at-risk teens before earning my master's degree at the University of Texas at Arlington.

The Thera eruption is not “generally accepted” as the cause of the Minoan demise, except on TV. The ash cloud was blown east not south, and the Minoans were thriving on Crete for at least 80 years after the blast. The Minoans were brought down by the invasion of the warlike Achaean Greeks ca. 1450 BC (See Roots of Cataclysm, Algora Publ.Ny 2009).

Actually, it is generally accepted by scholars that the eruption of Thera did, indeed, play a major role in the destruction of Knossos. Mycenaean Greeks certainly began occupation at around the same time and the two hypotheses are that these Greeks either invaded and caused the destruction levels found in Knossos or they migrated as a result of the destruction and re-throned Knossos under a new rule.

The prevailing winds at the time were actually southeast in various readings I’ve encountered, but regardless of that, the amount of volcanic ejecta was enough to still give an ash-fall at Knossos and Mallia that was in excess of 20 cm thick. Just half of this would have been sufficient to halt agricultural production. But it wasn’t the ash that would have been the most significant destructive factor. It would have been the earthquakes and subsequent Tsunamis. The ash cloud, moving southeast, deposited a layer of ash from Central to Eastern Crete which is still measured to be 78 cm thick today.

Its clear through pottery changes and texts that Mycenaean Greeks take over Crete at a period between 1470-1380 BCE, but it isn’t clear that they invaded prior to Thera’s eruption. It seems more likely that they were taking advantage of an opportunity to take over a weakened, all but obliterated, Knossos. Skeletal studies of human remains found in Knossos have supported this conclusion.

Castleden, Rodney (1990). Minoans: Life in Bronze Age Crete. New York: Routledge.

Evans J.D. (1968). Knossos Neolithic, Part II: Summary and conclusions. Annual of British School at Athens,63:267â€“276.

I would call to your attention Lesson 17 of “The Prehistoric Archaeology of the Aegean”(Dartmouth U.)which says in part: Western Crete would have been unaffected by the ashfall, but eastern Crete would have been covered by a maximim of 10 centimeters, more probably 1 to 5.” Also:”A tidal wave, if there was one, would not have been onanything like the scale envisaged by proponents of a link between Thera and the sudden decline of Neopalatial Crete.”

First, let me say thank you for coming back to comment. It’s always enjoyable to engage in discussions such as these.

Second, I may very well be wrong. But I think we’re in agreement that two hypotheses are 1) that the Thera eruption is responsible for the downfall of the Minoan civilization, and 2) Mycenaean invasion is responsible for the downfall of the Minoan civilization. The point of debate here between us seems to be what, specifically, is “generally accepted” as the cause for the collapse of the Minoan civilization. Regardless of what actually is.

Whether it is or isn’t, both hypotheses have had favor at various times over the years since Sir Arthur Evans first posited an earthquake hypothesis. But recent investigations have lent a lot of support to a combination of these, starting with years of eruptions at Santorini (Thera).

Bruins et al (2008) concluded that a tsunami in excess of 9 m at Palaikastro in north eastern Crete. The tsunami signatures in the geologic and archaeological strata showed evidence that tsunami waves reached the island after the ashfall. There’s no reason to conclude that tsunami waves didn’t also reach other points along the coast. But, to the point of what’s “generally accepted,” Bruins et al have this to say:

[T]he Santorini eruption and accompanying tsunami seem to have triggered the beginning of the end for the Minoans, whose major population centres were un-walled and largely situated along the coastline, and whose naval defence was probably devastated. Invasion and destruction followed in LM IB.

But they also point out that this would leave Crete ripe for the picking and that “[t]he gradual rebuilding and repopulation of Crete in the subsequent LM II and LM IIIA periods were controlled by a military minded authority that converted the Minoan Linear A script to suite the Greek language. This leaves little doubt that the invaders were Greeks from the mainland, Mycenae in particular, whose navy harboured in the protected Corinthian gulf.”

So, I admit that my “generally accepted” line above is based on an assumption. It seems clear that there are really two “generally accepted” facts: the eruption at Santorini was catastrophic and affected the Aegean islands; and the Minoan civilization was replaced by Mycenaean Greeks.

Thanks for this dialog. This is the sort of thing that prompts me to read more and investigate more thoroughly, getting past my assumptions.

I hope your gentle readers have found our banter as interesting as I have. I have to say though that I am dumbfounded by a couple aspects of the Bruin quote. The statement that the Minoan population was mostly coastal is quite accurate. The major population centers, such as Knossos and Phaistos, were completely untouched by the Thera eruption. Bruins also ignores the 80 year time gap between the blast and the Minoan fall. The idea that the Minoans would not have recovered from a 9 meter tsunami on their north coast within a very few years is implausible. I would conclude with a line from “The Discovery of Minoan Tsunami Deposits”(Geology, Jan.2000):”Whatever the true nature of the Minoan destruction, the tsunamis produced by the Santorini eruption could only have been a minor component. It is time to move on from this deeply flawed and unsustainable hypothesis.”